Resonant filter applications in electronic ballast

In this paper an analysis is presented of the resonant filter used in an electronic ballast through the phase angle from the input resonant filter current to the input resonant filter voltage. The proposed analysis allows evaluation of the resonant filter characteristics. The main characteristics that are analyzed are: lamp starting, soft commutation, DC current in the lamp, resonant filter influence in the converters and lamp pre-heating. This work allows a choice of the best filter to employ in an electronic ballast for fluorescent lamps.